Portable underwater fuel feed system

ABSTRACT

A portable underwater hydrazine feed system for feeding hydrazine to a hydrazine decomposition reactor. The gas from the reactor may be used to drive a power tool, a swimmer propulsion device or the like with the exhaust gas from the driven device being employed to drive a gas operated differential area piston pump. The gas operated pump forces water into a chamber containing hydrazine. The hydrazine is isolated from the water by a slidable piston or expandable bellows and is displaced into the hydrazine decomposition reactor by the water.

United States Patent 1 Geres PORTABLE UNDERWATER FUEL FEED SYSTEM [75]Inventor: Robert J. Geres, China Lake, Calif.

[73] Assignee: The United States of America as represented by theSecretary of the Navy, Washington, DC.

[22] Filed: Dec. 29, 19711 [21] Appl. No.: 213,573

[52] U.S. Cl ..60/643, 222/389 [51] Int. Cl C0611 5/04 [58] Field ofSearch 60/51, 39.48, 259, 37, 36,

[56] References Cited UNITED STATES PATENTS 3,101,592 8/1963 Robertsonet al. 60/37 3,436,914 4/1969 Rosfelder 3,525,217 8/1970 DeMattia et al60/37 [451 Feb. 19, 1974 3,667,216 5/1972 DeMattia 60/37 PrimaryExaminer-Edgar W. Geoghegan Assistant Examiner-H. Burks, Sr.

Attorney, Agent, or FirmR. S. Sciascia; Roy Miller; R. F. Beers [57]ABSTRACT A portable underwater hydrazine feed system for feedinghydrazine to a hydrazine decomposition reactor. The gas from the reactormay be used to drive a power tool, a swimmer propulsion device or thelike with the exhaust gas from the driven device being employed to drivea gas operated differential area piston pump. The gas operated pumpforces water into a chamber containing hydrazine. The hydrazine isisolated from the water by a slidable piston or expandable bellows andis displaced into the hydrazine decomposition reactor by the water.

5 Claims, 4 Drawing Figures PATENTEDFEBIBIQH 3792 580 SHEET 3 [1F 3 FIG.4.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionpertains to portable underwater hydrazine feed systems for feedinga-hydrazine decomposition reactor. I

2. Description of the Prior Art Gas generators have been usedextensively in missile systems for generating electrical power,providing gas for actuation of aerodynamic control surfaces, andproviding high-pressure gas for expulsion of fluids in liquid propulsionand thrust vector control (TVC) systems. Other gas generatorapplications include auxiliary power supplies for aircraft, torpedopropulsion, balloon inflation, buoyancy systems, and cartridge actuateddevices.

Solid propellants, liquid bipropellants, liquid monopropellants, hybridpropellants and the reaction of metallic hydrides and certain activemetals with water have all been considered for various gas generatorapplications. While the characteristics of these systems varyconsiderably, they are in general very attractive on an energy densitybasis (in many cases exceeding even the most exotic battery systems).However, specific energy or power parameters are very sensitive tosystemefficiency and the fuel mass ratio. Systems engineering istherefore particularly critical for gas generator power systems.

With development of the Shell 405 spontaneous catalyst for hydrazine, anew family of MGGs with demand restart capability, tailored exhaust gastemperature, and clean gas products isavailable. Hydrazine decomposes onthe catalyst in the gas generator to produce an exhaust gas consistingof hydrogen, nitrogen, and ammonia. The prepackaged demand gas generatorpower system of the present invention offers significant advantages overpresent systems such as high specific power input, low maintenance, longterm storage, simplicity of operation, portability, low noise, highfuel-tomass fraction, complete demand operation, and operation over awide range of environmental conditions through neutral buoyancy throughfuel depletion and depth insensitive fuel pressure differential. Thisunique combination of features presents significant improvements overexisting applications of batteries, compressed gas, and small internalcombustion engines.

Fo r'example, some systems today use direct gas pressurization i.e., theliquid hydrazine is displaced by gas from a source such as a bottle ofnitrogen. As the liquid hydrazine is displaced by a gas it is seen thatthe buoyancy of the entire device increases. When such a device is beingused by a diver to operate a tool, for example, the increased buoyancywould cause the diver to rise to the surface. Therefore, the need forneutral buoyancy is clearly seen.

Other prior art devices while maintaining a neutral I buoyancy, employ aspring expulsion system. A coil springis employed to move a piston in acylinder causing displacement of the liquid hydrazine. Such a systemdoes not provide a constant pressure differential between the hydrazinecontainer and its point of destination. This is because the spring forcedecreases as the I spring elongates. Alsodue to the weight of the springand piston, a poor fuel to mass fraction is presented i.e., the springand piston constitute too great a portion of the mass.

Elastomeric bags have also been used for hydrazine displacement,however, they too do not present a constant pressure differential.

Another disadvantage of direct gas pressurization as with a bottle ofnitrogen is that such a system does not have a depth insensitivefuel-pressure differential. For

example, the present device requires approximately v psi fuel pressuredifferential. To operate such a device below water at 1 1,000 psiambient pressure for example would require bottled nitrogen at 1 1,150psi. At

this pressure the size of the tank to hold the gas would be unweildable.The present invention, on the other hand, requires a pump capable ofpumping a displacement liquid such as sea water at only 150 psi overambient pressure.

The low noise characteristics of the present invention are especiallydesirable in underwater operations due to the high conductivity of noiseunderwater. This is especially true if the present invention were to beemployed for operating a relatively noisy tool.

The most important features of the present invention, however, are itslong term storage, low maintenance, and simplicity of operationthusleading to low production cost per unit. I I

SUMMARY OF THE INVENTION The present invention is a portable underwaterhydrazine feed system for feeding liquid hydrazine to a demand hydrazinedecomposition reactor. The present invention employs a boot strapoperation in which a gas operated pump forces surrounding water into a,chamber causing displacement of a piston or compres sion of a bellows orflexible bag. The piston, bellows or flexible bag are employed toisolate the hydrazine from the water. As water enters the chamber thehydrazine is forced into a hydrazine gas generator. The gas from thegenerator is employed to drive a gas driven tool with the exhaust fromthe tool being employed to drive the gas driven water pump.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. is a schematic of the boot strapoperation of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the inventionenclosed bya steel cylindrical pressure vesselll with a hydrazinechamber 12 and water chamber 13 separated by piston 14. Rubber o-ringsl6 and 17 serve to seal the water chamber from the hydrazine chamber.

The hydrazine is expelled into a hydrazine decomposition reactor 19 bydisplacing it with water which is pumped into pressure vessel 11 by gasoperated differential area piston pump 18. Ambient water enters the pumpthrough water inlet 21 and passes through pump 18 into water cavity 13through passageway 22. Gas for driving the pump enters through gas inlet23 which is connected to the exhaust24 of a gas driven motor 43.

Movement of pump 18 is initiated by the manual actuation of lever 26.

Hydrazine enters and exits chamber 12 through passageway 27 leading toquick disconnect 28. Upon loading chamber 12 with hydrazine, it isdesired that a predetermined amount of volume in vessel 11 be allowedfor hydrazine expansion. This is provided by ullage cylinder 29. As thepiston is forced upward towards the pump, the narrowneck portion 31 ofthe piston enters ullage cylinder 29 and water within the ullagecylinder is trapped after the top of portion 31 contacts rubber o-ring32 located in the circumference ofthe ullage cylinder. During loading,three way valve 36 prevents any flow from ullage cylinder 29 throughconduit 38. This prevents further movement of piston 14.

Water which is forced out of water cavity 13 passes through opening 33at the top of vessel 11 and through conduit 34, three way valve 36 andconduit 37 into the ambient water.

After chamber 12 is filled, the refueling means is disconnected at quickdisconnect 28 and three way valve 36 is actuated to prevent flow throughconduit 37 and to allow flow through conduit 38 into conduit 34. If thehydrazine within chamber 12 expands water trapped in ullage cylinder 29is allowed to escape through relief valve 35 as piston 14 rises. Thepressure in chamber 13 is released through the flow of water throughconduit 34 and safety relief valve 35.

In operation, lever 26 is pumped to actuate pump 18 causing a flow ofwater into water inlet 21 through pump 18 and through passageway 22 intochamber 13 thus forcing piston 14 downward against the hydrazine inchamber 12. The hydrazine is thus forced through passageway 27 and quickdisconnect 28. Quick disconnect 28 is connected to pressure feedbackfuel control valve 39 which allows passage of hydrazine into a hydrazinedecomposition reactor 19. The hydrazine decomposes-on the catalyst inthe gas generator to produce an exhaust gas consisting of hydrogen,nitrogen, ammonia, and heat. A portion of this gas passes throughfeedback conduit 41 to be used in regulating pressure feedback fuelcontrol valve 39 while the remainder of products from the reactor passthrough heat exchanger 42 and onto gas power tool 43 via flexible line44 quick disconnect 45 and safety release valve 46. The gas motor isemployed, to operate an underwater power tool, swimmer propulsion unitor the like.

Exhaust from motor 43 passes through quick disconnect 47, flexible hose48 and into gas inlet 23 of pump 18.

A first modification of the invention as shown in FIG. 2 employs apolyethylene bellows 249 as a hydrazine chamber with the remainder ofcylindrical pressure vessel 211 serving as the water chamber. As thedevice is refueled by filling bellows 249 via a fuel line connected toquick disconnect 228 and passageway 227, bellows 249 elongates forcingwater through opening 233 into conduit 234 and through two way valve 251into the ambient water.

After bellows 249 is filled, two way valve 251 is shut off so that nowater may flow through it thus allowing the only flow of water throughconduit 234 to pass through safety relief valve 235. This allows forexpansion of the hydrazine to force water out through safety reliefvalve 235. The hydrazine can now be forced out 4 of the bellows byallowing pump 218 to pump ambient sea water through inlet 221 andthrough passageway 222 into chamber 212. The pressurized water inchamber 212 causes the bellows to collapse forcing hydrazine throughconduit 22'! and out of quick disconnect 228. A third modificationoperates similar to the bellows arrangement. Thev third modificationshown in FIG. 3 employs a flexible polyethelene bag or self foldingrollonet 349 for containing the hydrazine. The second the thirdmodifications are otherwise similar in all respects with the elementsbeing numbered in the 300s and with the last two digits of eachreference numeral corresponding to the last two digits of the referencenumerals of the first and second modifications.

I claim:

1. A portable underwater fuel feed system, comprismg:

a fuel chamber charged with a predetermined amount of fuel;

a water chamber;

a gas-driver hydraulic pump for pumping ambient water into said waterchamber;

means in contact with the fuel and water for forcing fuel from said fuelchamber as water enters said water chamber;

a catalytic reactor;

a conduit connecting said fuel chamber to said reactor;

a gas driven motor;

a conduit connecting said reactor and'said motor for conveying the gasproducts from said reactor to said motor; and

a conduit connecting said motor and said pump for conveying the exhaustgas from said motor to said whereby the gas driven pump is controlled byexhaust gas from the motor to allow a flow of water into the waterchamber causing pressurized fuel to be delivered to the reactor forproducing a supply of gas sufficient to drive the motor.

2. The system of claim 1 further comprising:

a pressure feedback fuel control valve located in said conduitconnecting said fuel changer to said reactor;

means conveying gas pressure information at the exit end of said reactortosaid valve;

whereby said pressure remains essentially constant.

3. The system of claim 1 wherein said fuel forcing means comprises:

a cylindrical container;

a piston slidable along the axis of said container; and

a self folding rollonet attached to the bottom of said container andlocated within said container.

1. A portable underwater fuel feed system, comprising: a fuel chambercharged with a predetermined amount of fuel; a water chamber; agas-driver hydraulic pump for pumping ambient water into said waterchamber; means in contact with the fuel and water for forcing fuel fromsaid fuel chamber as water enters said water chamber; a catalyticreactor; a conduit connecting said fuel chamber to said reactor; a gasdriven motor; a conduit connecting said reactor and said motor forconveying the gas products from said reactor to said motor; and aconduit connecting said motor and said pump for conveying the exhaustgas from said motor to said pump; whereby the gas driven pump iscontrolled by exhaust gas from the motor to allow a flow of water intothe water chamber causing pressurized fuel to be delivered to thereactor for producing a supply of gas sufficient to drive the motor. 2.The system of claim 1 further comprising: a pressure feedback fuelcontrol valve located in said conduit connecting said fuel changer tosaid reactor; means conveying gas pressure information at the exit endof said reactor to said valve; whereby said pressure remains essentiallyconstant.
 3. The system of claim 1 wherein said fuel forcing meanscomprises: a cylindrical container; a piston slidable along the axis ofsaid container; and said piston dividing said container into said waterchamber and said hydrazine chamber.
 4. The system of claim 1 whereinsaid fuel forcing means comprises: a cylindrical container; and apolyethylene bellows attached to the bottom of said container andlocated within said container.
 5. The system of claim 1 wherein saidfuel forcing means comprises: a cylindrical container; and a selffolding rollonet attached to the bottom of said container and locatedwithin said container.